This invention relates to that described and claimed in application Ser. No. 932,141 filed Aug. 9, 1978 and assigned to the same assignee as this application.
The forementioned application describes a microprocessor control system for affecting channel selection and function level adjustments. The system uses an electrically alterable ROM to store television broadcast station or channel information which is retrieved by the microprocessor and converted by a digital-to-analog converter into voltages for use by a varactor tuner to tune in channels on a television receiver. Should the electrically alterable ROM lose some or all of the channel information stored in it, a repairman would have to reinsert that information manually in order for the receiver to be able to be tuned to the channels corresponding to the lost information. Alternatively the microprocessor could have stored in its internal ROMs all of the channel information which was also stored in the electrically alterable ROM. Neither of these alternatives is acceptable. The former because it would require the repairman to expend an inordinate amount of time in order to insert this information manually into the ROM. The latter because the duplication would use up too much of the capacity of the internal ROMs.